鄂尔多斯盆地延安地区本溪组高分辨率层序地层与沉积特征
High-resolution sequence stratigraphy and sedimentary characteristics of Benxi Formation in Yan'an area of Ordos Basin
范萌萌 1袁珍 2李文厚 3卜军4
作者信息
- 1. 西安科技大学地质与环境学院/陕西省煤炭绿色开采地质保障重点实验室,陕西西安 710054
- 2. 西安石油大学地球科学与工程学院,陕西西安 710065;陕西省油气成藏地质学重点实验室,陕西西安 710065
- 3. 西北大学地质学系/大陆动力学国家重点实验室,陕西西安 710069
- 4. 中国石油长庆油田分公司油气工艺研究院/低渗透油气田勘探开发国家工程实验室,陕西西安 710021
- 折叠
摘要
鄂尔多斯盆地延安地区油气资源储藏丰富,本溪组是重要的勘探层段之一,但其沉积环境复杂,砂体分布及沉积演化特征不明确,制约了该地区天然气勘探开发的进程.因此,加强对延安地区本溪组地质学方面的研究,尤其是层序地层、沉积特征及演化的研究,将对该地区的古地理重建、油气勘探及开发提供有利的理论支撑.以高分辨率层序地层学、沉积岩石学、测井地质学和沉积学为理论指导,研究了鄂尔多斯盆地延安地区晚古生代本溪组的地层和沉积特征,确定了其层序地层单元划分、等时地层格架、沉积相类型及演化过程.研究结果表明,在层序地层方面,本溪组内可以识别出1个长期基准面旋回、2个中期基准面旋回和多个短期旋回;在沉积相类型方面,识别出12种岩石类型和7种岩相组合,据此认为延安地区本溪组发育潮坪和障壁岛—潟湖沉积相,进而识别出潮道、砂坪、混合坪、泥坪、泥炭坪、障壁岛砂坝、潟湖泥等沉积微相;在沉积相展布方面,研究区西南部和南部以潮坪沉积为主,东北部和北部以障壁岛—潟湖沉积为主,本1段和本2段的沉积格局基本一致.
Abstract
The oil and gas resources in Yan'an area of Ordos Basin are abundant,and Benxi Formation is one of the important exploration intervals.However,its sedimentary environment is complex,and the distribu-tion of sand bodies and sedimentary evolution characteristics are not clear,which restricts the process of natu-ral gas exploration and development in this area.Therefore,strengthening the study of geology of Benxi Forma-tion in Yan'an area,especially the study of sequence stratigraphy,sedimentary characteristics and evolution,will provide favorable theoretical support for paleogeographic reconstruction,oil and gas exploration and devel-opment in this area.Based on the theories of high-resolution sequence stratigraphy,sedimentary petrology,logging geology and sedimentology,the stratigraphic and sedimentary characteristics of the late Paleozoic Benxi Formation in Yan'an area of Ordos Basin were studied,and the sequence stratigraphic unit division,isochro-nous stratigraphic framework,sedimentary facies types and evolution process were determined.The results show that in terms of sequence stratigraphy,one long-term base-level cycle,two medium-term base-level cy-cles and multiple short-term cycles can be identified in Benxi Formation.In terms of sedimentary facies types,12 types of lithofacies and 7 lithofacies combinations were identified.According to this,it is considered that tidal flat and barrier island-lagoon sedimentary facies were developed in Benxi Formation in Yan'an area,and sedimentary microfacies such as tidal channel,sand flat,mixed flat,mud flat,peat flat,barrier island and la-goon sediments were identified.In terms of sedimentary facies distribution,tidal flat deposits are mainly devel-oped in the southwest and south,and barrier island-lagoon deposits are mainly developed in the northeast and north.The sedimentary patterns of Ben 1 section and Ben 2 section are basically consistent.
关键词
高分辨率层序地层学/沉积演化/本溪组/延安地区/鄂尔多斯盆地Key words
high-resolution sequence stratigraphy/sedimentary evolution/Benxi Formation/Yan'an area/Ordos Basin引用本文复制引用
出版年
2024
NETL
NSTL
万方数据